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Several important models of machine learning algorithms have been successfully generalized to the quantum world, with potential speedup to training classical classifiers and applications to data analytics in quantum physics that can be…

Quantum Physics · Physics 2021-10-01 Ji Guan , Wang Fang , Mingsheng Ying

We investigate for which resource states an efficient classical simulation of measurement based quantum computation is possible. We show that the Schmidt--rank width, a measure recently introduced to assess universality of resource states,…

Quantum Physics · Physics 2009-11-13 M. Van den Nest , W. Dür , G. Vidal , H. J. Briegel

It has been found that the quantum-to-classical transition can be observed independent of macroscopicity of the quantum state for a fixed degree of fuzziness in the coarsened references of measurements. Here, a general situation, that is…

Quantum Physics · Physics 2017-05-10 Dong Xie , An Min Wang

The classicality of the Gamma Model, an analytically solvable quantum oscillator with non-linear dynamics, is investigated using the overlap dynamics, also known as the Loschmidt Echo, and roughness, a classicality measure based on the…

Quantum Physics · Physics 2025-12-23 Gilson V. Soares , Mauricio Reis , Adelcio C. Oliveira

For a given quantum state used in sensing, the quantum Cram\'er-Rao bound (QCRB) sets a fundamental limit on the precision achievable by an unbiased estimator of an unknown parameter, determined by the inverse of the quantum Fisher…

Quantum Physics · Physics 2026-01-14 Andrew Kolmer Forbes , Marco A. Rodríguez-García , Ivan H. Deutsch

A new measure of non-classical correlations is introduced and characterized. It tests the ability of using a state {\rho} of a composite system AB as a probe for a quantum illumination task [e.g. see S. Lloyd, Science 321, 1463 (2008)], in…

Quantum Physics · Physics 2014-07-17 A. Farace , A. De Pasquale , L. Rigovacca , V. Giovannetti

The existence of incompatible measurements, epitomized by Heisenberg's uncertainty principle, is one of the distinctive features of quantum theory. So far, quantum incompatibility has been studied for measurements that test the preparation…

Quantum Physics · Physics 2017-03-16 Michal Sedlak , Daniel Reitzner , Giulio Chiribella , Mario Ziman

We study the problem of quantum-state tomography under the assumption that the state of the system is close to pure. In this context, an efficient measurements that one typically formulates uniquely identify a pure state from within the set…

Quantum Physics · Physics 2016-05-11 Amir Kalev , Charles H. Baldwin , Ivan H. Deutsch

We present two possible criteria quantifying the degree of classicality of an arbitrary (finite dimensional) dynamical system. The inputs for these criteria are the classical dynamical structure of the system together with the quantum and…

Quantum Physics · Physics 2007-05-23 Nuno Costa Dias

Originally introduced as the difference between two possible forms of quantum mutual information, quantum discord has posteriorly been shown to admit a formulation according to which it measures a distance between the state under scrutiny…

Quantum Physics · Physics 2018-10-01 P. R. Dieguez , R. M. Angelo

Consumption of magic states promotes the stabilizer model of computation to universal quantum computation. Here, we propose three different classical algorithms for simulating such universal quantum circuits, and characterize them by…

Quantum Physics · Physics 2021-03-23 James R. Seddon , Bartosz Regula , Hakop Pashayan , Yingkai Ouyang , Earl T. Campbell

The true dynamical randomness is obtained as a natural fundamental property of deterministic quantum systems. It provides quantum chaos passing to the classical dynamical chaos under the ordinary semiclassical transition, which extends the…

chao-dyn · Physics 2008-02-03 Andrei P. Kirilyuk

We derive exceedingly simple practical procedures revealing the quantum nature of states and measurements by the violation of classical upper bounds on the statistics of arbitrary measurements. Data analysis is minimum and definite…

Quantum Physics · Physics 2009-04-28 Ángel Rivas , Alfredo Luis

We propose the Wigner separability entropy as a measure of complexity of a quantum state. This quantity measures the number of terms that effectively contribute to the Schmidt decomposition of the Wigner function with respect to a chosen…

Quantum Physics · Physics 2012-05-23 Giuliano Benenti , Gabriel G. Carlo , Tomaz Prosen

We provide a compendium of inequalities between several quantum state distinguishability measures. For each measure these inequalities consist of the sharpest possible upper and lower bounds in terms of another measure. Some of these…

Quantum Physics · Physics 2014-10-24 Koenraad M. R. Audenaert

We extend the definition of quantum discord as a quantifier of nonClassical correlations in a quantum state to the case where weak measurements are performed on subsystem $A$ of a bipartite system $AB$. The properties of weak discord are…

Quantum Physics · Physics 2015-12-01 Lekshmi S , N Shaji , Anil Shaji

The different time-dependent distances of two arbitrarily close quantum or classical-statistical states to a third fixed state are shown to imply an experimentally relevant notion of state sensitivity to initial conditions. A quantitative…

Quantum Physics · Physics 2007-05-23 Gonzalo Garcia de Polavieja

In quantum physics, the density operator completely describes the state. Instead, in classical physics the mean value of every physical quantity is evaluated by means of a probability distribution. We study the possibility to describe pure…

Quantum Physics · Physics 2011-11-09 Alberto Montina

The notion of complexity of quantum states is quite different from uncertainty or information contents, and involves the tradeoff between its classical and quantum features. In this work, we we introduce a quantifier of complexity of…

Quantum Physics · Physics 2025-11-26 Siting Tang , Francesco Albarelli , Yue Zhang , Shunlong Luo , Matteo G. A. Paris

While negativity in phase space is a well-known signature of nonclassicality, a wide variety of nonclassical states require their characterization beyond negativity. We establish a framework of nonclassicality in phase space that addresses…

Quantum Physics · Physics 2021-12-30 Jiyong Park , Jaehak Lee , Hyunchul Nha